slop: add page (#4741)

pages/linux/slop.md

@@ -0,0 +1,24 @@
+# slop
+
+> Get a selection of the screen.
+> More information: <https://github.com/naelstrof/slop>.
+
+- Wait for the user to make a selection and output its geometry to standard output:
+
+`slop`
+
+- Double click, rather than click and drag, to draw a selection:
+
+`slop -D`
+
+- Highlight the selection rather than outlining it:
+
+`slop -l`
+
+- Specify the output format:
+
+`slop -f {{format_string}}`
+
+- Specify the selection rectangle's color:
+
+`slop -c {{red}},{{green}},{{blue}},{{alpha}}`